diff --git a/src/guard.c b/src/guard.c
index a7fa1a97a..55f189b6c 100644
--- a/src/guard.c
+++ b/src/guard.c
@@ -24,17 +24,18 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include "monsters.h"
 
 #include <kernel/ally.h>
-#include <kernel/unit.h>
+#include <kernel/building.h>
 #include <kernel/faction.h>
 #include <kernel/race.h>
 #include <kernel/region.h>
-#include <kernel/building.h>
+#include <kernel/terrain.h>
+#include <kernel/unit.h>
 
 #include <assert.h>
 
 guard_t can_start_guarding(const unit * u)
 {
-    if (!u->region->land) {
+    if (u->region->terrain->flags & SEA_REGION) {
         return E_GUARD_TERRAIN;
     }
     if (u->status >= ST_FLEE || fval(u, UFL_FLEEING))
@@ -72,7 +73,6 @@ void setguard(unit * u, bool enabled)
     } else {
         assert(!fval(u, UFL_MOVED));
         assert(u->status < ST_FLEE);
-        assert(u->region->land);
         fset(u, UFL_GUARD);
         fset(u->region, RF_GUARDED);
     }
diff --git a/src/guard.test.c b/src/guard.test.c
index cc59af4d8..8302bcc9a 100644
--- a/src/guard.test.c
+++ b/src/guard.test.c
@@ -140,7 +140,7 @@ static void test_update_guard(CuTest * tc)
 
     test_setup();
     t_ocean = test_create_terrain("ocean", SEA_REGION);
-    t_plain = test_create_terrain("plain", LAND_REGION);
+    t_plain = test_create_terrain("packice", ARCTIC_REGION);
     itype = it_get_or_create(rt_get_or_create("sword"));
     new_weapontype(itype, 0, frac_zero, NULL, 0, 0, 0, SK_MELEE, 2);
     r = test_create_region(0, 0, t_plain);
@@ -181,6 +181,13 @@ static void test_guard_on(CuTest * tc)
     guard_on_cmd(ug, ug->thisorder);
     CuAssertTrue(tc, is_guard(ug));
 
+    terraform_region(r, test_create_terrain("packice", ARCTIC_REGION));
+
+    setguard(ug, false);
+    CuAssertIntEquals(tc, E_GUARD_OK, can_start_guarding(ug));
+    guard_on_cmd(ug, ug->thisorder);
+    CuAssertTrue(tc, is_guard(ug));
+
     terraform_region(r, t_ocean);
 
     setguard(ug, false);
@@ -189,13 +196,6 @@ static void test_guard_on(CuTest * tc)
     CuAssertTrue(tc, !is_guard(ug));
     CuAssertPtrNotNull(tc, test_find_messagetype(ug->faction->msgs, "error2"));
 
-    setguard(ug, false);
-    t_ocean->flags &= ~ SEA_REGION;
-    CuAssertIntEquals(tc, E_GUARD_TERRAIN, can_start_guarding(ug));
-    guard_on_cmd(ug, ug->thisorder);
-    CuAssertTrue(tc, !is_guard(ug));
-    CuAssertPtrNotNull(tc, test_find_messagetype(ug->faction->msgs, "error_onlandonly"));
-
     terraform_region(r, t_plain);
 
     i_change(&ug->items, itype, -1);
diff --git a/src/laws.c b/src/laws.c
index dfbd163cb..3d996971b 100644
--- a/src/laws.c
+++ b/src/laws.c
@@ -2699,12 +2699,7 @@ int guard_on_cmd(unit * u, struct order *ord)
             setguard(u, true);
         }
         else if (err == E_GUARD_TERRAIN) {
-            if (fval(u->region->terrain, SEA_REGION)) {
-                cmistake(u, ord, 2, MSG_EVENT);
-            }
-            else {
-                ADDMSG(&u->faction->msgs, msg_feedback(u, ord, "error_onlandonly", ""));
-            }
+            cmistake(u, ord, 2, MSG_EVENT);
         }
         else if (err == E_GUARD_UNARMED) {
             ADDMSG(&u->faction->msgs, msg_feedback(u, ord, "unit_unarmed", ""));